I'm on firm 4.1.0 & these are the results of my tests
SX OS + LayeredFS = Freeze
Hekate + LayeredFS = Devmenu working ok (unable to install nsp because the signature bypass)
Both cases using SMO as donor
--------------------- MERGED ---------------------------
So, why don't you wait for next sx os update?, clearly it's something wrong with the os that could be fixed in next releases considering that layeredfs is working on 4.1 with hekate.
I should wait next sx os update, but I'm a bit impatient... By the way, eshop games doesn't require specific firmware version ?